Proposal to study factors involved in the control of antibody binding affinity and heterogeneity of affinity. Computational methods have been developed to describe the distribution of affinities in an antibody sample using data obtained by equilibrium dialysis. The effect of antigen dose, time after immunization, boosting and tolerance induction on heterogeneity of antibody affinity and the distribution of antibody affinities will be determined. We will also carry out breeding experiments to look for evidence for genetic control of the affinity of antibody synthesized. The purpose is to gain increased understanding of the selective factors involved in the control of the immune response.